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Fresh Water
relatively pure, with few dissolved salts
Only 2.5% of Earth’s water is fresh
Most freshwater is tied up in glaciers and ice caps
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Tributary
a smaller river slowing into a larger one
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Watershed
-the area of land drained by a river and its tributaries
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Floodplain
areas nearest to the river’s course that are flooded periodically
-Frequent deposition of silt makes floodplain soils fertile
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Riparian
•riverside areas that are productive and species-rich
•Water of rivers and streams hosts diverse ecological communities
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Wetlands
systems that combine elements of freshwater and dry land
Wetlands are extremely valuable for wildlife
- They slow runoff
- Reduce flooding
- Recharge aquifers
- Filter pollutants
- People have drained wetlands, mostly for agriculture
- Southern Canada and the U.S. have lost more than half of their wetlands
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Freshwater Marshes
shallow water allows plants to grow above the water’s surface
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Swamps
shallow water that occurs in forested areas
-Can be created by beavers
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Bogs
ponds covered in thick floating mats of vegetation
-A stage in aquatic succession
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Littoral Zone
region ringing the edge of a water body
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Benthic Zone
extends along the entire bottom of the water body
Home to many invertebrates
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Limnetic Zone
open portions of the lake or pond where the sunlight penetrates the shallow waters
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Profundal Zone
water that sunlight does not reach
Supports fewer animals because there is less oxygen
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Oligotrophic lakes and ponds
have low nutrient and high oxygen conditions
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Eutrophic lakes/ponds
have high nutrient and low oxygen conditions
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Inland Seas
large lakes that hold so much water, their biota is adapted to open water
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Groundwater
- Any precipitation that does not evaporate, flow into waterways, or get taken up by organisms
- Groundwater makes up one fifth of the Earth’s freshwatersupply
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Aquifiers
Porous sponge-like formations of rock, sand, or gravel that hold groundwater
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Zone of Aeration
pore spaces are partially filled with water
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Zone of Saturation
Spaces that are completely filled with water
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Water Table
Spaces between Aeration and Saturation Zones
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Aquifier Recharge zone
any area where water infiltrates Earth’s surface and reaches aquifers
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Confined Aquifier
water-bearing, porous rocks are trapped between layers of less permeable substrate (i.e., clay)
-Is under a lot of pressure
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Unconfined Aquifier
no upper layer to confine it
-Readily recharged by surface water
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The Ogallala Aquifer
•Underlies the Great Plains of the U.S.
- •Its water has allowed farmers to create the
- most bountiful grain-producing region in the world
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